Coupling



.externally threaded, mating member 2.

Patented Feb. 28, 1950 Robert Lovell, Nutley, N. J., assigner to The Nylok Corporation, New AYork, N.` Y., la corporation of Delaware Application April 1, 1947, serial No. 738,589

The invention 'herein disclosed relates to a coupling especially adapted for uniting the ends of ltwo hollow elements. "Couplings of the kind mentioned are used to lunite the ends of successive hollow. elements which encase certain elements, or carry fluids. The more common use for such couplings is in connecting iiuid conductors such Aas oil lines, hose and the like. vMany such couplings are used on vvarious applications where they are subjected f to vibration and shock of such nature as'to tend to loosen the coupling. In cases of this kind where a loose coupling may result in serious complications, such for example as an airplane oil line or a spark plug coupling, the couplings must be checked and tightened at regular intervals.

, An object of 'this invention is to provide a cou- "pling of the kind mentioned which includes male and female threaded members and in which 'a locking action is effected between the threads of vthe members. Another object of the invention iis to provide a coupling of this kind invwhich a resilient element is utilized to effect the locking 'action between the threads of the members. A "further object of the invention is to provide ra coupling of this kind in which the locking ele- ,ment forms a part of one of the members.

The foregoing objects and certainv advantages The drawing includes: y Fig. 1 which is a side elevation, partly in section, of a coupling embodying the invention;

Fig. 2 which is a side elevation of the internally threaded, female member of the coupling; and

Fig. 3 which is an enlarged, fragmentary sectional elevation of the threaded portion of the coupling members and illustrating the locking action.

The coupling illustrated in the. drawing primarily consists of two mating, threaded members, an internally threaded, female member I and an The internally threaded member is of hexagonal outer conguration and includes a body portion 3 and an extenson or collar Il at one end thereof. The v outer configuration is hexagonal lto provide six wrench faces 5 that may be engaged by a wrench for tightening the coupling.

The member I is hollow and adapted to be rotatably secured on a tubular element 6 which constitutes one of the elements to be coupled to- .3 claims. (o1. 2st-#ssl gether. A portion I of the member I is undercut internally to approximately the depth of the root y of the thread 8. The end of this undercut portion terminates in 'a frustro-conical wall 9 which constitutes the inner surface of an inwardly ex# tending, circumambient end flange Ill. rIhe mem ber l is litted over the tubular element 6 and the lend of the element is flared outwardly to form an `outwardly extending end flange I I that is frustroh conical and Wall 9.

The member 2 has a thready I2,fformed or cut on the outer surface thereof, which'thread is the same as the thread 8 of the member I l and mates therewith. The end portion I3 of the member 3 which enters the member I, is frustro-conical in shape. At the end of the threaded portion of the member 2, opposite to the conical end I3, there is provided a hexagonal portion I4 to provide wrench faces I5. This member is secured v to one yend of a tubular element I6 which constitutes the other of the two elements to be coupled together.

In coupling the elements 6 and I6 together, the member 2 is threaded into the member I. The conical end I3 of the member' 2 is drawn home, tightly, against the flange II of the element 5. A fluid tight joint is thus assured as long as the end portionr I3 of the member 2 is retained in comparable to the frustro-conical ltight clamping relation withthe flange I I, which,

under .such circumstances, is clamped between theend portion I3 and the inner wall 9 of the inwardly extending flange III. i'

tight. However, in most applications and particu- Ilarly on moving vehicles, such couplings are subjected to vibration and shock which tends to effect relative rotation of the members in a direction to loosen 'the connection. To avoid such loosening of the coupling, the coupling illustrated inthe drawing is constructed and arranged to eiect' a frictional locking action between the threads of the members. Y For this purpose, a resilient element Il is provided in the member I. The wall of the member I is drilled radially to form a shouldered hole therethrough. Into this hole the resilient element I1 is inserted and makes a close iit therein so that it is restrained in all directions laterally of the axis thereof. The element I'I is positioned in the hole in the wall of the member I so that the inner end thereof extends inwardly beyond the root of the thread 8 and desirably is tangent to the circle of the minor diameter of the thread. The length of the element I1 is less than the epsilonaminocaproamide,

thickness of the wall of the member I, and it is positioned as above described. The element I'I is restrained against radially inward movement by a shoulder I'Ia formed thereon and engaging the shoulder formed in the hole through the wall, and against radially outward movement by a circumferential tang I8. The tang I8 is desirably cut from the wall of the hole in the member I and bent over the end of the resilient element I1.

Desirably, the resilient element II is a plug of non-metallic, resilient material. materials are suitable for this purpose, certain of the polyamides derived from polyamide-forming materials of the class consisting of aminocarboxylic acids and mixtures of polyamines with polycarboxylic acids. Such polyamides are While several metallic, resilient insert Within the hole in the side Wall, the resilient insert being restrained available on the market under the designation of nylonf Polyamides particularly suitable for the present purpose include polyhexamethylene adipamide, polyhexamethylene sebacamide, polypolytetramethylene adipamide, polyhexamethylene terephthalamide, and mixtures of these polyamides. Especially desirable are the synthetic linear polyamides melting at comparatively high temperatures, above one hundred degrees centigrade.

With the construction above described, upon the engagement of the threads of the members I and '2, the members are displaced transverse to the axis to effect a misalignment thereof and cause a frictional, locking engagement between the threads. This condition or relation is illustrated in Fig. 3 of the drawing. As the thread of the member 2 engages the plug Il, the plug is compressed but exerts a resilient force acting radially between the members I and 2. This -force causes the portions of the threads l8 and I2 opposite to the plug to engage in intimate, surface contact so that a frictional locking force is effected between the surfaces thereof.

In effect, over approximately half of the circumference, the threads are wedged together, the

vtolerance being taken up at the plug I'I as illustrated. It is this thread engagement that effects vthe locking action because when nylon is used as the resilient element, the coefficient of fric- .tion between the nylon and the thread is mate- -rially less than the coefficient of friction of the engaging threads. Nylon also has many other advantages which include the fact that it is not affected by oils and grease and the fact that when compressed and released, it tends to return to its original shape. This latter characteristic makes it particularly desirable as the coupling may be disconnected and reconnected repeatedly without materially affecting the locking action. With a nylon insert, the frictional engagement effected 4between the threads of the members I and 2 is sufficient to preventloosening of the members under vibration and shock ordinarily encountered in service.

against lateral and outward movement and extending inwardly beyond the root of the thread, whereby upon engagement with an externally threaded, mating coupling member, the members are displaced transversely of the axis thereof and a frictional, locking engagement is effected between the threads of the members.

2. As a new article or" manufacture, a coupling, suitable for coupling two hollow elements together, which coupling comprises in combination an internally threaded, female member adapted to be rotatably secured to one of the elements to be coupled together and having a single radial opening through the wall thereof, a resilient insert secured in the radial opening in the side wall of the female member, the resilient insert being restrained against lateral and outward movement and extending inwardly beyond the root of the thread of the female member, and a mating, externally threaded male member adapted to be secured to the other of the two elements to be coupled together, the resilient insert of the female member engaging the thread of the male member and displacing the mating threaded element transversely of the axis thereof, whereby a frictional locking engagement between the threads of the mating threaded elements is effected.

3. As an article of manufacture, a hollow, internally threaded coupling member adapted to engage in threaded engagement with a mated threaded coupling member having an external thread thereon, the internally threaded coupling member having a radial hole in the side walls thereof, a resilient insert secured within the hole in the side wall, the resilient insert being restrained against lateral and outward movement and extending inwardly beyond the root of the thread, and being of lesser length than the thickness of the wall, whereby upon engagement with an externally threaded, mating coupling member, the members are displaced transversely of the axis thereof by the action of the resilient element engaging the thread of the mating coupling member and a frictional locking engagement is effected between the threads of the members opposite the resilient insert.

ROBERT LOVELL.

REFERENCES C ITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

